1. Field of the Invention
The present invention relates to the field of power drivers, and more particularly to a novel seated driver having direct current motor drive through a pair of wheels which is detachably connected to a mobile carriage mounting a floor finishing device such as a sanding drum wherein the seated driver includes speed and directional controls.
2. Brief Description of the Prior Art
In the past, it has been the conventional practice to prepare and/or finish a wooden floor surface by employing an apparatus having a sanding drum which is maneuvered over the wood surface in order to prepare or finish the surface. Conventional apparatus generally includes a mobile carriage having a sanding drum which is maneuvered over a floor surface by means of a hydraulic powered driver unit. The driver unit is usually coupled to the mobile carriage and a seat is provided on the driver unit for accommodating the operator who steers the apparatus via a steering mechanism carried on the mobile carriage.
Although successful for finishing or refinishing a wooden floor surface, conventional apparatus has experienced difficulties and problems which stem largely from the fact that the driver unit incorporates hydraulic mechanisms which are extremely heavy in weight and require periodic maintenance. Also, such prior apparatus is difficult to control with respect to speed and direction since all controls must be coupled into the hydraulic system in order to operate. Hydraulic driver units are generally dirty since such units require oil reservoirs or high pressure hydraulic fluid lines which have a tendency to leak. Some attempts have been made to avoid the situation by using alternating current driving units but the use of alternating current requires excessive wattage and high draw or drain of electricity.
Therefore, a long-standing need has existed to provide a novel floor accessory apparatus which includes an improved driving unit that is light in weight, includes direct current power drive and incorporates speed and direction controls which are operated from DC power. The units should also include improved electrical and mechanical connection between the driving unit and the mobile carriage or driven unit so that special knowledge or extensive installation or hookup mechanisms are not required.
Accordingly, the above problems and difficulties have been avoided by the present invention which provides a novel floor accessory driver, particularly for use in connection with floor sanding procedures, which includes a driven unit having a sanding drum carried on a wheeled chassis which in turn is detachably connected to a driver unit that includes a seat on which the operator sits and further includes a DC driving means for electrically powering a set of wheels. Operation of the electrical system is under the foot control of the operator via a pivoting treadle for controlling forward and reverse direction of the driver unit and for simultaneously controlling the speed of the driving unit. A maximum speed control is also connected to the electrical circuit which may be preset by the operator. In one form of the invention, foot treadle includes an eccentric cam which positions a cam follower to operate a microswitch that controls speed. Direction of travel, either forward or in reverse, is under control of the foot pedal via potentiometers which are connected at opposite ends of the treadle so as to operate alternately as the treadle is pivoted.
The invention further includes a tongue-in-groove arrangement for detachably connecting the driver unit to the mobile driven unit which may include a yoke into which a loop is inserted and wherein the yoke and loop are maintained in contact by a keeper bolt or pin. The hitch or coupling permits limited pivotal movement which is useful in permitting the operator to steer the mobile unit via a hand-steering means carried on the end of a column projecting from the top of the mobile unit. The mobile unit further includes an AC current control for a sanding wheel and an electrical power cable is detachably connected to the steering column which, in turn, is connected to the AC motor.
The driver unit includes a chassis which supports the DC drive motor and since an electrical drive system is provided, the structure and weight of the driver unit is greatly reduced as compared to hydraulic operated systems.
Therefore, it is among the primary objects of the present invention to provide a novel combined driver unit and driven unit which are coupled together by a pivotal hitch and wherein the driver unit includes a DC drive so that the weight and complexity of the driver unit is greatly reduced as compared with hydraulic systems and structures.
Another object of the present invention is to provide a driver unit which includes a reversible foot switch mechanism that is pivoted so as to alternately operate potentiometers in order to determine reverse or forward direction as well as to control speed.
Another object of the present invention is to provide a fully electronic floor sanding driver which is less than half the size of other floor sanding drivers and which is significantly lighter than other floor sanding drivers.
Still a further object resides in providing a floor sanding driver and driven unit that can be used in confined areas such as residential applications as well as in large commercial areas such as gymnasiums or the like.
The present invention further resides in the provision of two types of speed control which is operated by a foot pedal and a maximum speed potentiometer.
Another object resides in providing adjustments to a DC electrical system for rate of acceleration and deceleration with respect to control of a driver unit.
Further objects include compensation for load such as maintaining constant and/or even speed as well as providing independent control for roward/reverse speeds.
A further object of the invention resides in providing an electrical system for driving a driver unit which draws only 25% of electricity that other floor sanding drivers require.